CRUSHER APPARATUS

Abstract: A gyratory crusher for crushing rock and the like comprises a mantle driven in an orbital motion within a concave shell. The mantle is imported at its lower end by a thrust bearing system including upper and lower spherical roller bearings which cooperate to carry the axial thrust. The lower end part of the mantle is journalled within the upper of the two spherical bearings and the lower one of the two bearings which supports the upper bearing is centred on the axis of the shell. The roller bearing arrangement leads to reduced lubrication requirements and can carry a higher degree of overload thrust than can slide bearings as conventionally used in crushers of this type.

Description: CRUSHER APPARATUS The present invention relates to crusher apparatus for crushing rock and other minerals, and more particularly to crusher apparatus of the type comprising a gyratory conical crushing element. Gyratory rock and mineral crushers conventionally comprise an outer stationary shell of generally conical form having an internal lining of a hardened steel, such as manganese steel, which is sometimes known as the "concave", and a conical crushing element which has an outer lining likewise of manganese or other hardened steel. The crushing element is sometimes known as the "mantle" and is eccentrically mounted with respect to the axis of the outer shell or concave whereby the mantle is driven in an orbital or gyratory motion around the axis of the concave, which defines the main vertical axis of the machine. Rock or other mineral material is fed into the crushing chamber which is defined between the interior surface of the concave and exterior surface of the mantle and the orbital or gyratory motion of the mantle exerts a crushing action on the material as it moves downwardly through the crushing chamber. In previously proposed crushers of this type, the mantle is supported from below by a bearing system which includes an axial thrust bearing which carries the main axial thrust on the mantle in opposition to the axial components of the crushing forces generated between the mantle and concave. The mantle itself has a relatively complex motion which is a combination of the orbital motion around the machine axis and a rotational motion about its own axis, and conventionally the main axial thrust bearing by which the mantle is supported from below is in the form of a spherical slide bearing which can readily accommodate this complex motion. The slide bearing is subject to extremely heavy loading during crushing and the bearing surfaces require very effective lubrication. The lubrication requirements for the bearing are severe and a relatively complex lubrication system, including oil coolers, is usually necessary. Although slide thrust bearings can carry a degree of overload above their normal design limit, care does need to be exercised in the operation of the crusher to ensure that an excessive overload situation does not occur and which might lead to failure of the bearing. In crushers of the type discussed above, the mantle is often mounted for vertical displacement within the concave by means of a hydraulic cylinder. The lower bearing system including the axial thrust bearing is supported from the hydraulic cylinder which is used to adjust the vertical position of the mantle within the concave. This adjustment serves to vary the crushing pressure and the size of the crushed matter and also serves to compensate for wear of the steel on the concave and mantle; it also permits the mantle to be moved to a lowered position in order to release matter which may have become blocked between the mantle and concave. The geometry of the bearing system in previously proposed crushers is such that adjustment in the height of the mantle causes variation in the eccentricity of the mantle and this, in turn, causes variation in the driving torque applied to the mantle. In particular, as the mantle is raised as may be required to compensate for wear, the eccentricity tends to reduce which causes a reduction in the driving torque. According to the present invention there is provided crushing apparatus of the type comprising a conical mantle mounted within a conical shell with a crushing chamber being defined between an interior surface of the shell and an exterior surface of the mantle, and means for mounting the mantle such that the longitudinal axis of the mande is able to orbit around the longitudinal axis of the shell and d e mantle is able to rotate about its longitudinal axis, wherein the mounting means comprises an upper bearing system for mounting the mantle at its upper end, and a lower bearing system for mounting the mande at its lower end and for carrying axial thrust generated during crushing, the lower bearing system comprising a first roller thrust bearing for carrying axial thrust, the first roller bearing having an axis coincident with the axis of the shell, and a second roller thrust bearing for carrying axial thrust, the second bearing having an axis displaced from the longitudinal axis of the shell and die second bearing being supported from the first bearing and serving to support the mantle whereby the mantle is supported from the first bearing via the second bearing, the first and second bearings being spherical roller bearings. In a preferred configuration, the lower bearing system also comprises a radial thrust bearing for the mantle, the radial thrust bearing being a spherical roller bearing having an outer race with a spherical surface centred at a point on the axis of the mande, and a lower race of die second bearing is also defined by a spherical surface centred at said point. The upper bearing system preferably defines an upper swivel point at a point of intersection of the longitudinal axis of the mantle with the longitudinal axis of the shell and die mande is mounted for axial displacement relative to d e shell together widi the lower and upper bearing systems including die upper swivel point, whereby to permit adjustment of the position of the mantle relative to the shell without affecting the bearing geometry. Such axial displacement can be effected by means of a fluid cylinder, such as a hydraulic cylinder, from which the mande is supported via d e lower bearing system. An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a cross-section of a crusher in accordance widi the preferred embodiment of d e invention; Figure 2 is a cross-section to an enlarged scale showing a lower bearing system of die crusher; and Figure 3 is a cross-section to an enlarged scale showing an upper bearing system of the crusher. The crusher shown in the accompanying drawings comprises a concave shown at 2 and a conical mande shown at 4. A crushing chamber 6 is defined between the concave 2 and mantle 4 to receive rock and od er minerals to be crushed and which is fed into die chamber 6 through an upper feed inlet, material crushed by the action of the mande 4 leaving die crushing chamber 6 from below. The basic construction and operation of the concave 2 and mantle 4 is conventional and will not be described in detail. The mantle 4 includes upper and lower main shafts 8, 10 located on the longitudinal axis A j of the mantle 4 and by which the mantle 4 is mounted within the machine for its rotational and gyratory or orbital motion. The upper main shaft 8 is mounted widiin an upper spherical bearing system 12 which will be described in detail hereinafter, to permit the mande 4 to rotate at its upper end about a point 0^ which lies on the longitudinal axis A2 of the concave and which can be considered to be d e main longitudinal axis of the machine. The longitudinal axis A j is inclined relative to die longitudinal axis A2 and point 0 j is at the point of intersection of these two axes. The lower main shaft 10 is supported from a lower hydraulic cylinder 14 via a lower bearing system 16, the cylinder 14 being actuable to raise and lower die mande 4 relative to die concave 2 in order to permit adjustments of die type described earlier. The lower bearing system 16 will be described in detail hereinafter and comprises axial and radial d rust bearings which permit the longitudinal axis A of the mande 4 to orbit around die longitudinal axis A2 of die concave 2, with diis orbital movement being centred on the point 0 j defined at die upper bearing system 12; d e bearings also permit the mande 4 to rotate about its own longitudinal axis A j _. The main drive system for the mande 4 comprises an eccentric 20 which is journalled for rotation about the main longitudinal axis A2 of the machine, the eccentric 20 being driven from a drive shaft 21 through a driving gear train which, in the embodiment shown, comprises bevel gears 22, 24. Spherical roller bearings by which the eccentric 20 is journalled widiin die main frame of the machine are shown at 25. With reference to Figure 2, the eccentric 20 is of sleeve-like or tubular form within which the lower main shaft 10 is mounted and has an interior cylindrical surface 26 which is eccentric relative to the main longitudinal axis A2 of the machine. The lower main shaft 10 is journalled within die eccentric 20 by means of a radial thrust bearing which forms a part of the lower bearing system 16. The radial dirust bearing comprises inner and outer races 28, 30 and upper and lower sets of spherical rollers 32 between the two races. The outer race 30 is of spherical form of radius R j centred at a point O2 which lies on the longitudinal axis A j of the mantle 4. It will be seen from the drawings d at die longitudinal axis A^ of the mantle 4 is inclined by a few degrees to die longitudinal axis A2 of the machine about the upper swivel point 0 j and the inner race 28 of the radial thrust bearing is inclined relative to d e outer race 30 by a corresponding amount. When the eccentric 20 is driven, the eccentricity of its cylindrical inner surface 26 drives die mantle 4 via the radial dirust bearing to cause the mande 4 to orbit around die longitudinal axis A2 of the machine. The radius of die orbital motion is dependent on die eccentricity of the eccentric 20 and reduces progressively from the lower to die upper end of die mantle as the upper swivel point 0^ for the mande is coincident widi the longitudinal axis of the machine. Unlike in previously proposed crushers of this type in which the main axial thrust is carried by a slide bearing, the lower bearing system 16 of the preferred embodiment of the invention incorporates roller bearings for this purpose, as will now be described in detail. The axial thrust bearings of the lower bearing system 16 comprise a lower axial thrust bearing 36 adjacent the hydraulic cylinder 14 and an upper axial thrust bearing 40 adjacent the main shaft 10. The lower thrust bearing 36 comprises spherical rollers 44 and the axis of this bearing is coincident widi die main longitudinal axis A2 of the machine. The upper race 46 of the lower thrust bearing 36 faces downwardly and inwardly towards d e lower race 48 of that bearing and carries a plate 50 which supports the upper thrust bearing 40. The upper thrust bearing 40 is also a spherical roller bearing with a lower race 52 which lies outwardly of, and faces inwardly towards, the upper race 54. The longitudinal axis of the upper dirust bearing 40 is parallel to the longitudinal axis A2 of the machine and is spaced ti erefrom by a distance "d". The lower race 52 has a spherical surface of radius R2 centred on die point O2 which is also the centre of the spherical surface defining the outer race 30 of the radial thrust bearing. The displacement "d" is also the same as the displacement between the point O2 and d e longitudinal axis A2 of the machine as measured in a horizontal plane passing through the point O2. The axial end face of die lower main shaft is supported from the upper race 54 of the upper bearing 40 via a profiled support ring 56 which seats against the end face of die main shaft 10 and also against the inner race 28 of the radial thrust bearing. The double spherical roller bearing arrangement of the lower bearing system 16, with die axis of the upper thrust bearing being offset from the longitudinal axis of the machine as described above, accommodates the orbital and rotary motion of the mantle about different axes, one inclined relative to d e other. During this motion, the upper race 54 of die upper thrust bearing 40 will execute a wobbling motion relative to the lower race 52 about the point O2. The support plate 50 by which the upper and lower dirust bearings 40, 36 are connected rotates wid d e eccentric 20, but due to manufacturing tolerances within the bearing system may also wobble slighdy during d e motion; in order to accommodate diis wobbling motion whilst ensuring that the plate 50 rotates with die eccentric 20, die plate 50 is coupled to d e eccentric 20 by a longitudinal keyed or splined connection. A seal 55 is interposed between the mande and die main frame of the machine to prevent ingress of dust and dirt to d e lower bearing system, and die lower bearing system may also be subject to a positive air pressure so tiiat diere is an outflow of air which prevents entry of dust or dirt. Widi reference to Figure 3, the upper bearing system 12 for the upper main shaft 8 comprises a spherical slide bearing having an inner convex bearing shell 60 carried by the upper main shaft 8 mounted within an outer convex bearing shell 62, the bearing surfaces of the shells being of spherical form centred at die point 0 j . The outer shell 62 is supported widiin a sleeve 64 which is movable axially within an upper cylinder 66, the axis of movement of the sleeve 64 and outer bearing shell 62 being coincident with the longitudinal axis A2 of the machine. Widi diis configuration, when the lower hydraulic cylinder 14 is actuated to raise and lower d e mantle 4, die whole of the lower bearing system 16, including d e radial and axial thrust bearings and point O2 will move with the mantle, and die upper bearing system 12 including point 0 j will also move with the mande 4. Accordingly, die geometry of the mounting system by which the mande 4 is mounted at its upper and lower ends does not alter with variations in the axial position of the mantle 4 relative to the eccentric 20 and the concave 2 and dierefore a constant driving torque can be achieved throughout the range of adjustment. In the embodiment shown, the machine has provision for adjustment of the eccentricity of the eccentric 20 and for this purpose, and as shown in Figure 2, the sleeve which forms the eccentric comprises a tubular outer body 20a wid an inner eccentric cylindrical surface and a tubular inner body 20b having an outer cylindrical surface seated against the eccentric surface of the outer body 20a and an inner eccentric surface. The outer race 30 of the radial dirust bearing is mounted widiin die inner surface of the inner body 20b. The overall eccentricity can be altered by rotating the inner body 20b widiin die outer body 20a and locking the inner body 20a in its selected position. When this facility is provided, the support plate 50 between die upper and lower axial thrust bearings 40, 36 carries an eccentric mounting plate 70 which is similarly rotated in order to vary d e eccentricity of the mounting of die upper dirust bearing 40 to account for the changed eccentricity of the overall drive system. The use of a roller bearing system to carry the main axial thrust of the mande leads to significantly reduced lubrication requirements for the bearing system and hence a simplified lubrication system. Also roller bearings can carry a significandy greater overload dian can a slide bearing without incurring damage. The embodiment has been described by way of example only and modifications are possible within the scope of the invention.

Claims: CLAIMS :- 1. Crushing apparatus of the type comprising a conical mande mounted widiin a conical shell with a crushing chamber being defined between an interior surface of the shell and an exterior surface of the mande, and means for mounting the mande such that die longitudinal axis of the mande is able to orbit around die longitudinal axis of the shell and the mande is able to rotate about its longitudinal axis, wherein the mounting means comprises an upper bearing system for mounting the mande at its upper end, and a lower bearing system for mounting the mande at its lower end and for carrying axial thrust generated during crushing, the lower bearing system comprising a first roller thrust bearing for carrying axial thrust, the first roller bearing having an axis coincident widi die axis of the shell, and a second roller thrust bearing for carrying axial thrust, the second bearing having an axis displaced from the longitudinal axis of the shell and die second bearing being supported from the first bearing and serving to support die mande whereby die mande is supported from the first bearing via the second bearing, the first and second bearings being spherical roller bearings. 2. Crushing apparatus according to claim 1, wherein the lower bearing system further comprises a radial thrust bearing for the mantle, the radial dirust bearing being a spherical roller bearing having an outer race with a spherical surface centred at a point (O2) on the axis of the mantle, and a lower race of the second spherical axial thrust bearing is also defined by a spherical surface centred at said point (O2). 3. Crushing apparatus according to claim 1 or claim 2, wherein the first roller bearing has a lower race which faces upwardly and outwardly, and an upper race which faces downwardly and inwardly, and the second roller bearing has a lower race which faces upwardly and inwardly, and an upper race which faces downwardly and outwardly, the arrangement being such that axial thrust is transmitted to die lower bearing system via the upper race of the second roller bearing. 4. Crushing apparatus according to claim 3, wherein the longitudinal axis of the second roller bearing is displaced from, but parallel to, the longitudinal axis of the shell. 5. Crushing apparatus according to claims 2 and 4, wherein d e distance (d) by which die longitudinal axes of die first and second roller bearings are displaced is equal to die distance between the said point (O2) and the longitudinal axis of the shell in a horizontal plane passing through said point (O2). 6. Crushing apparatus according to any one of claims 1 to 5, wherein the longitudinal axes of die mande and shell intersect at a point (0^) and d e upper bearing system defines for the mantle an upper swivel point coincident widi die said point of intersection (0 j ). 7. Crushing apparatus according to claim 6, wherein die upper bearing system comprises a spherical bearing having bearing surfaces centred at said point of intersection (0 j ). 8. Crushing apparatus according to claim 6 or claim 7, further comprising means for adjustably mounting d e mantle and lower bearing system for axial displacement relative to die shell, said upper bearing system being movable axially with die mantle to thereby maintain a fixed spatial relationship between the upper and lower bearing systems which is unaffected by the axial position of the mantle relative to die shell. 9. Crushing apparatus according to claim 8, wherein the means for adjustably mounting the mantle comprises a fluid cylinder from which the first roller bearing is supported whereby adjustment of the axial position of the mantle is effected by adjustment of the axial position of the lower bearing system by means of the fluid cylinder. 10. Crushing apparatus according to claim 1, wherein the lower bearing system further comprises a radial thrust bearing for the mantle, said radial dirust bearing having an outer race mounted within a cylindrical inner surface of an eccentric which is driven to cause the orbital motion of the mande, said apparatus further comprising means for adjustably mounting die mande and lower bearing system for axial displacement relative to die shell, said upper bearing system being movable axially with die mande whereby to maintain a fixed spatial relationship between the upper and lower bearing systems which is unaffected by die axial position of the mande relative to the shell, the driving eccentricity of die eccentric also being unaffected by the axial position of the mantle relative to the shell.

Inventors: MCKENZIE IAN WALTER, MCKENZIE, IAN, WALTER
Applicants: CLYDE IND LTD, MCKENZIE IAN WALTER, CLYDE INDUSTRIES LIMITED TRADING AS JAQUES, MCKENZIE, IAN, WALTER
Application year: 1994
Main classification: B02C2
IPC codes: B02C2